In HTTP Adaptive Streaming (HAS), video content is temporally divided into multiple segments, each encoded at several quality levels. The client can adapt the requested video quality to network changes, generally resulting in a smoother playback. Unfortunately, live streaming solutions still often suffer from playout freezes and a large end-to-end delay. By reducing the segment duration, the client can use a smaller temporal buffer and respond even faster to network changes. However, since segments are requested subsequently, this approach is susceptible to high round-trip times. In this letter, we discuss the merits of an HTTP/2 push-based approach. We present the details of a measurement study on the available bandwidth in real 4G/LTE networks, and analyze the induced bit rate overhead for HEVCencoded video segments with a sub-second duration. Through an extensive evaluation with the generated video content, we show that the proposed approach results in a higher video quality (+7.5%) and a lower freeze time (-50.4%), and allows to reduce the live delay compared to traditional solutions over HTTP/1.1.

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HTTP Adaptive Streaming (HAS) is today the number one video technology for over-the-top video distribution. In HAS, video content is temporally divided into multiple segments and encoded at different quality levels. A client selects and retrieves per segment the most suited quality version to create a seamless playout. Despite the ability of HAS to deal with changing network conditions, HAS-based live streaming often suffers from freezes in the playout due to buffer under-run, low average quality, large camera-to-display delay, and large initial/channel-change delay. Recently, IETF has standardized HTTP/2, a new version of the HTTP protocol that provides new features for reducing the page load time in Web browsing. In this paper, we present ten novel HTTP/2-based methods to improve the quality of experience of HAS. Our main contribution is the design and evaluation of a push-based approach for live streaming in which super-short segments are pushed from server to client as soon as they become available. We show that with an RTT of 300 ms, this approach can reduce the average server-todisplay delay by 90.1 % and the average start-up delay by 40.1 %.

Omnidirectional video (cylindrical or spherical) is a new media becoming more and more popular thanks to its interactivity for online multimedia applications such as Google Street View as well as for video surveillance and robotics applications. Interactivity in this context means that the user is able to explore and navigate audio-visual scenes by freely choosing viewpoint and viewing direction. In order to provide this key feature, omnidirectional video is typically represented as a classical two-dimensional (2D) rectangular panorama video that is mapped onto a (spherical or cylindrical) mesh and then rendered on the client's screen. Early transmission models of this full panorama video and mesh content simply deal with the panorama as a highresolution video to be encoded at uniform quality. Generally the user can only view a restricted field-of-view of the content and then interact with pan-tilt-zoom commands. This means that a significant part of the bandwidth is wasted by transmitting quality video in regions that are not being visualized. In this paper we evaluate the relevance and optimality of a personalized transmission where quality is modulated in spherical or cylindrical regions depending on their likelihood to be viewed during a live user interaction. We show, based on interaction delay as well as bandwidth constraints, how tiling and predictive methods can improve on existing methods. © 2012 Alcatel-Lucent. heritage [3] and has since moved towards video with higher resolution and higher quality thanks to the evolution of omnidirectional capture devices.Interactivity, in this context, refers to the fact that the user is able to explore and navigate into audiovisual scenes by freely choosing a viewpoint and viewing direction. In order to provide this key feature, omnidirectional video is typically represented as a classical two-dimensional (2D) rectangular panorama with cylindrical projection into latitude and longitude [15]

The potential of 3D printing to revolutionize manufacturing is becoming today a reality. Also referred to a class of Additive Manufacturing (AM) technologies, 3D printing enables mass customization and manufacturing of device components, parts of houses, human organs and even food. It reduces production costs, manufacturing time, and necessary storage space. Due to this success, the protection of Intellectual Property Rights (IPR) for 3D printed models raises increased concerns. Among technologies enabling copyright protection, traitor tracing and authentication, 3D watermarking has received a lot of interest from the research community in the context of 3D digital models.In this paper we give an overview of the state of the art of 3D digital watermarking and we assess how it could be extended for ensuring the IPR protection of printed 3D models. By considering 3D printing and scanning as an attack, we evaluate the potential of state-of-the-art watermarking techniques to provide both robust protection and also high fidelity as the introduced shape perturbations should not impair the mechanical properties or functionalities of the printed 3D model. Categories and Subject DescriptorsI.4.10 [Image Representation] Volumetric representation including watermarking of the surface for IPR protection of models in the context of 3D printing.